266 GASTROPODA. [Pectinibranchia. 



Sect. 1. COLPOSPIRA. Donald, 

 Colpospira, Donald, P. Mai. S., iv, 51. Tj^pe : Turritella runcinata, Watson. 



Shell having the aperture subquadrate, rather longer than wide ; 

 outer lip arched obliquely backwards above a deep sinus, then pro- 

 duced prominently below the sinus, and curved round to meet the 

 columella, where it is slightly canaliculated. 



Distinguished from the type and other sections of Turritella by the 

 deep sinus in the outer lip, by the lower part of the lip being more 

 produced forwards, by the columella being longer and nearly straight, 

 and by the aperture being slightly channelled below. 



KEY TO SPECIES. 



a. Shell with 1 prominent spiral cord on the lower whorls. . . . pagoda. 



b. Shell with 2 prominent spiral cords on all the post-nuclear whorls ; 



angle of spire, 15-18 . . . . . . . . . . fulminata. 



c. Shell with 3 prominent spiral cords on a whorl . . symmetrirn. 



d. Shell with (> prominent spiral cords on a whorl . . . . chordata. 



e. Shell with 2 principal, 2 secondary, and some finer cords on the 



lower whorls ; angle of spire, 18 . . . . . . Carlottce. 



f. Shell with 4 principal cords on the fourth to seventh whorl, and 2 



strong cinguli on the lower whorls . . . . difftcilis. 



;/. Lower whorls with 2-3 principal and 2-3 secondary cords, besides 

 fine threads ; sometimes all of nearly equal strength ; angle 

 of spire, 20-22 ; shell large . . . . . . . . rosca. 



1. Turritella Carlottae, Watson, 1881. Plate 39, fig. 19. 



Tnrritell(i Carlottce, Wats., J.L.S., xv, 1881, 222 ; Chall. Rep., xv, 478, 

 pi. 30, f. 5 ; Murdoch and Suter, T.N.Z.I., xxxviii, 292 ; Suter, I.e., 

 327. T. vittaiu, Button, C.M.M., 29 ; M.N.Z.M., 84 ; Index, 76 ; not 

 of Lamarck. 



Shell high, narrow, conical, thin, translucent, with fine ruddy 

 spiral threads, a slightly impressed suture, and an angular flattened 

 base. Sculpture : Longitudinals there are fine, thread-like, close-set, 

 curved lines of growth ; spirals there are 2 principal, 2 secondary, 

 and very many minor spirals, but the relative value of these varies 

 a good deal ; they are little raised, but distinct ; the base is covered 

 with line crowded spirals, of which those near the edge are stronger 

 than the rest ; the microscopic system of spirals is fine, sharp, and 

 distinct. Colour yellowish ashv-white, with a suffused ruddy-brown 



/ *J 



on the upper part of the whorls, and a stronger shade of the same 

 colour defining the move important spirals; the colour becomes al- 

 together paler up the spire, and the apex is white. The epidermis 

 is a very thin and delicate calcareous membrane, obviously not ex- 

 traneous ; it adheres to the top of the spirals and stretches across 

 their furrows ; it is sparsely cleft by minute gaping rents in the direc- 

 tion of the lines of growth, and the microscopic sculpture of the shell 

 is traceable in it, but rather on its under than its upper surface. S}/'< 



